Soil Compaction Effects
30 Questions
7 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is an incorrect method to reach ZAV?

  • Encryption
  • Zero compaction (correct)
  • Decompression
  • Compression

    • What is a characteristic of ZAV access?

  • Requires zero compaction
  • Needs encryption
  • Involves compression
  • Cannot be reached (correct)

    • What is true about accessing ZAV?

  • It uses zero compaction
  • It requires a specific algorithm
  • It involves data encryption
  • It cannot be accessed (correct)

    • What is a limitation of ZAV?

    <p>It cannot be reached by zero compaction</p> Signup and view all the answers

    What is not a method to access ZAV?

    <p>Zero compaction</p> Signup and view all the answers

    What is false about ZAV?

    <p>It can be reached by zero compaction</p> Signup and view all the answers

    What is a restriction on accessing ZAV?

    <p>It cannot be accessed</p> Signup and view all the answers

    What is not possible with ZAV?

    <p>Accessing through zero compaction</p> Signup and view all the answers

    What is a limitation on ZAV accessibility?

    <p>It cannot be accessed</p> Signup and view all the answers

    What is not a characteristic of ZAV access?

    <p>Cannot be reached</p> Signup and view all the answers

    What happens to the air voids in a compacted soil sample when it reaches its maximum degree of compaction?

    <p>They are completely removed</p> Signup and view all the answers

    What is the significance of achieving a degree of compaction where all air voids are removed?

    <p>It results in a high dry density</p> Signup and view all the answers

    What would be the likely effect on the compaction curve if the soil sample is not fully compacted?

    <p>The dry density would be lower</p> Signup and view all the answers

    What is the primary cause of entrapped air in a soil sample during compaction?

    <p>Insufficient compactive effort</p> Signup and view all the answers

    Which of the following would NOT affect the compactive effort required to achieve a certain degree of compaction?

    <p>Atmospheric pressure</p> Signup and view all the answers

    What is the purpose of the Standard Proctor Equipment in soil compaction testing?

    <p>To compact the soil to its maximum density</p> Signup and view all the answers

    How does the presence of entrapped air affect the dry density of a compacted soil sample?

    <p>It decreases the dry density</p> Signup and view all the answers

    What happens to the compaction curve when the soil sample is over-compacted?

    <p>The dry density decreases</p> Signup and view all the answers

    What is the effect of increasing the compactive effort on the dry density of a compacted soil sample?

    <p>The dry density increases</p> Signup and view all the answers

    What is the significance of determining the maximum dry density of a soil sample?

    <p>It is an important property in geotechnical engineering</p> Signup and view all the answers

    How many times is the soil compacted for each lift in the Modified Proctor Test?

    <p>25 times</p> Signup and view all the answers

    What was the Modified Proctor Test developed during?

    <p>World War II</p> Signup and view all the answers

    What is the primary purpose of compacting a soil sample?

    <p>To remove all air voids</p> Signup and view all the answers

    What happens to the dry density of a compacted soil sample when it reaches its maximum degree of compaction?

    <p>It increases</p> Signup and view all the answers

    What is the effect of entrapped air on the dry density of a compacted soil sample?

    <p>It decreases the dry density</p> Signup and view all the answers

    What is the significance of the Standard Proctor Equipment in soil compaction testing?

    <p>To compact the soil and determine its maximum dry density</p> Signup and view all the answers

    What happens to the compaction curve when the soil sample is over-compacted?

    <p>It becomes flatter</p> Signup and view all the answers

    What is the effect of increasing the compactive effort on the dry density of a compacted soil sample?

    <p>It increases the dry density</p> Signup and view all the answers

    What is the primary cause of entrapped air in a soil sample during compaction?

    <p>Insufficient compactive effort</p> Signup and view all the answers

    Why is it important to remove all air voids from a compacted soil sample?

    <p>To achieve maximum dry density and stability</p> Signup and view all the answers

    Study Notes

    Compaction Process

    • The compaction process is assumed not to decrease the volume of solids or soil grains.

    Effects of Compaction

    • Increases shear strength, density, and bearing capacity of soil.
    • Allows for larger loads to be applied to compacted soils due to their increased strength.

    Mechanism of Compaction

    Cohesive Principles

    • Interaction between adsorbed layer and interpretable force.
    • Breaking up of old bonds and establishment of new bonds between particles.
    • Bending and distortion of soil particles.

    Cohesionless Principles

    • Rearrangement of soil grains.
    • Breaking up of some cementation.
    • Bending and distortion of soil particles.

    Theories of Compaction

    • Lambe theory: physico-chemical concept.
    • Proctor theory (1933): lubrication theory, where water addition causes a thin layer to be absorbed by soil grains, increasing the layer with more water.

    Role of Water in Compaction

    • Water lubricates soil grains (cohesionless soil), allowing them to slide easily and achieve a denser arrangement.
    • Water expansion of the double layer, leading to a more orderly arrangement of particles, resulting in higher density (clayey soil).

    Phase Diagram

    • For a given water content w, the maximum density (ZAV) cannot be reached by compaction.

    Soil Compaction

    • Objective: increase density, strength, bearing capacity, and reduce permeability and compressibility
    • Laboratory work: obtain maximum dry density and optimum water content
    • Field compaction: executed by contractors using rollers and compactors

    Compaction Process

    • Definition: increasing soil unit weight by reducing the soil void ratio using mechanical devices
    • Modified Proctor Test: compacting soil in five layers with a 10 Lbs hammer, 18 inches drop height, and 25 blows/layer
    • Modified Proctor Energy: 56,250 ft-lb/ft³, calculated by (25 blows/layer) * (5 layers) * (10 lbs) * (1.5 ft) / (1/30) ft³

    Comparison of Standard and Modified Proctor Tests

    • Mold size: 1/30 ft³ for both tests
    • Standard Proctor Test: 12" height of drop, 5.5 lb hammer, 3 layers, 25 blows/layer, and energy 12,375 ft-lb/ft³
    • Modified Proctor Test: 18" height of drop, 10 lb hammer, 5 layers, 25 blows/layer, and energy 56,250 ft-lb/ft³

    Compaction Procedure in Lab

    • Method: removing air voids to achieve a degree of compaction (S=1)
    • Water content: wW / vt vw

    Soil Compaction

    • Objective: Increase density, strength, bearing capacity, and reduce permeability and compressibility
    • Laboratory work: Obtain maximum dry density and optimum water content
    • Field Compaction: Contractors use rollers and compactors to achieve compaction

    Compaction Process

    • Definition: Increasing soil unit weight by reducing soil void ratio using mechanical devices
    • Reduces permeability and compressibility

    Modified Proctor Test

    • Similar to Standard Proctor Test with exceptions:
      • Soil compacted in five layers
      • Hammer weight: 10 lbs or 4.54 kg
      • Drop height: 18 inches or 45.72 cm
      • Calculated energy: 56,250 ft-lb/ft³

    Standard Proctor Test

    • Mold size: 1/30 ft³
    • Drop height: 12 inches
    • Hammer weight: 5.5 lbs
    • 3 layers
    • 25 blows/layer
    • Energy: 12,375 ft-lb/ft³

    Compaction Procedure in Lab

    • Method: Drop hammer 25 times onto confined soil
    • Soil divided into three lifts, each compacted 25 times
    • Done 4-6 times from dry to wet
    • Goal: Achieve maximum dry density and optimum water content

    History of Modified Proctor Test

    • Developed during World War II
    • By the U.S.

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Related Documents

    Soil Compaction PDF

    Description

    This quiz covers the effects of soil compaction, including increased shear strength, density, and bearing capacity. It explores how compaction enables larger loads to be applied to soils.

    More Like This

    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser